Under normal operating conditions, an electric brake system for an aircraft relies upon an active power source, e.g., a power supply that is driven by the aircraft engine or engines. Such an active power supply can provide sufficient energy to drive the electric brake actuators on the aircraft, which may require relatively high drive power. There are, however, certain situations where aircraft rely upon backup power supplies. For example, an aircraft may utilize a battery (when the aircraft engines are not running) during towing, maintenance, or parking brake adjustment operations.
An electric brake system, which is normally utilized during towing operations, can place high power demands on a backup power supply whether or not the brake mechanisms are being actuated. Consequently, an electric brake system can cause rapid discharging of the backup power supply if the electric brake system is not shut down promptly following towing operations. Moreover, many systems on an aircraft are not required during certain operations that rely upon a backup power supply (such as towing). If any nonessential aircraft systems remain active during such operations, the backup power supply can be unnecessarily taxed to the point where it may not be able to adequately support the needs of more important functions, such as the electric brake system.